JP3535295B2 - Axial force measurement bolt - Google Patents
Axial force measurement boltInfo
- Publication number
- JP3535295B2 JP3535295B2 JP00317796A JP317796A JP3535295B2 JP 3535295 B2 JP3535295 B2 JP 3535295B2 JP 00317796 A JP00317796 A JP 00317796A JP 317796 A JP317796 A JP 317796A JP 3535295 B2 JP3535295 B2 JP 3535295B2
- Authority
- JP
- Japan
- Prior art keywords
- bolt
- axial force
- shear bolt
- ultrasonic
- shear
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Landscapes
- Force Measurement Appropriate To Specific Purposes (AREA)
Description
【発明の詳細な説明】
【０００１】
【発明の属する技術分野】本発明は、主に建築構造物
や、電車、自動車等の輸送機に用いられるボルトの締結
時の軸力を精度よくかつ容易に測定することができるボ
ルト構造に関するものである。
【０００２】
【従来の技術】例えばボルト・ナットによる締結力を用
いて建築構造物等を構築するに当り、その締結に用いら
れているボルト・ナットが所定の締付けトルクで締結さ
れているか否かを検出するための手段として、超音波を
用いる軸力測定する方法が知られている。
【０００３】まず超音波による締付けボルトの軸力測定
の原理について説明すると、ボルトの締め付け前後での
初期音速と片道伝搬時間差の積、すなわち超音波での伸
び量と実際の弾性伸び量の間には比例関係が成り立つ。
従って超音波の伸び量を弾性伸び量に換算し、換算した
伸び量をボルトのコンプライアンス（ばね定数の逆数）
で除算して軸力を算出することができる。
【０００４】
【発明が解決しようとする課題】そこで建築構造物等に
より広く用いられている例えばトルシア形高力ボルト
（以下シアボルトと称す）において、その軸力を超音波
により測定することの要求があるが、特にシアボルトの
従来の軸力測定では、以下の如き問題点があった。
【０００５】つまり、シアボルトは図３に示すように、
そのシアボルト１の先端にネック部２を介してピンテー
ル３が一体に形成されており、このシアボルト１を用い
て被締結部材６Ａ，６Ｂを一体に結合するには、シアボ
ルト１にナット５を螺着して被締結部材６Ａ，６Ｂの締
付けを行なうとき、ピンテール３に工具を係合させてシ
アボルト１の回動を阻止しながらナット５によるねじ締
めを行ない、そして締付けトルクの反力によりピンテー
ル３がネック部で切断された時点でねじ締めが完了され
る。
【０００６】このようにしてシアボルト１による被締結
部材６Ａ，６Ｂの締結後、そのシアボルトの軸力を測定
するためには、前記のように、締結前及び締結後のシア
ボルト１の頭面１Ａに超音波センサー４を当てがって測
定するが、締結前のシアボルト全長は、頭面１Ａからピ
ンテール３の端面３Ａまでの間であり、また締結後のシ
アボルト全長は、頭面１Ａからネック部切断面２Ａまで
の間であって、締結の前後では、シアボルト１の長さが
変化してしまう。従って軸力が発生していても、ボルト
の長さは締め付け後の方が締め付け前よりねじ切られた
ピンテール３の分だけ短くなり、正しい軸力測定が行な
えないという問題点があった。
【０００７】
【０００８】本発明は、かかる従来の問題点に着目して
なされたもので、締結後のシアボルトの軸力を超音波セ
ンサーを用いて精度よく測定することができる軸力測定
ボルトの提供を目的とするものである。
【０００９】
【課題を解決するための手段】この目的を達成するため
に本発明では、ナットが噛合されるボルトの先端に、ネ
ック部を介してピンテールが一体形成されているトルシ
ア形高力ボルトにおいて、上記ネック部位置よりトルシ
ア形高力ボルトの頭部側位置に、超音波反射部を形成し
た軸力測定ボルトであることを特徴としている。
【００１０】
【発明の実施の形態】以下に本発明を図面に示す実施形
態に基いて詳細に説明するが、本実施形態の構造と、従
来例で説明した構造との同一部分は、従来例で使用した
符号を引用して、その同一構造部分の構造説明は省略す
る。
【００１１】すなわち本実施形態では、シアボルト１の
ネック部とナット５の噛合部との間に超音波反射部７を
設けたことにある。
【００１２】この超音波反射部７は、シアボルト１の頭
面に当接された超音波センサー４からシアボルト１の軸
方向へ照射される超音波が反射される構造であればよ
く、この実施形態ではシアボルト１の直径方向に貫通す
る約２ｍｍの口径である透孔であるが、これに限られる
ものではなく、窪み穴、スリット等であってもよい。
【００１３】またこの超音波反射部７の施し位置は、こ
の実施形態では、ネック部２とナット５のねじ噛み合い
終了部との間に設けているが、これに限られるものでは
なく、ナット５の噛合部であってもよい。
【００１４】しかしながら、シアボルトの軸力を測定す
るには、その超音波反射部７の位置が、ピンテール３が
切断された後のシアボルト１の頭面１Ａより可及的に長
い距離であることが望ましいことから超音波反射部位置
は自ずと、ネック部近傍位置となる。
【００１５】次に上記構造のシアボルト１における軸力
測定手順について説明する。
【００１６】先ず測定準備と校正実験を行なうが、測定
準備では、超音波センサー４がシアボルト１の頭面１Ａ
に密着されるように、そのシアボルト１の頭面１Ａを切
削加工する。
【００１７】また校正実験は、シアボルト１の頭面に超
音波センサー４を設置し、次いでそのシアボルト１に、
引張り試験機等により負荷を与えるが、この負荷を与え
る前と後との超音波伝搬時間差とシアボルトの伸びの関
係を求め、これを材料定数とする。
【００１８】上記シアボルトの実際の軸力測定は、該シ
アボルト１を、被締結部材６Ａ，６Ｂにセットし、この
シアボルト１の頭面１Ａに超音波センサー４を当接して
締付け前のボルト超音波伝搬時間を、超音波反射部７に
よる反射波を用いて計測する。
【００１９】次にそのシアボルト１を専用の動力式ねじ
締め機によりピンテール３が、ネック部２より切断され
るまでナット５を回転させる。かくして締付けが完了し
たら、締付け前と同様に、ねじ締めされているシアボル
ト１の頭面１Ａに超音波を当接して締付け後の超音波伝
搬時間を超音波反射部７による反射波を用いて計測す
る。
【００２０】これによってシアボルト１の締付け前と後
との超音波の伝搬時間差と、前記材料定数とによってシ
アボルトのコンプライアンス等から軸力を算出すること
ができる。
【００２１】
【００２２】
【発明の効果】このように本発明によればシアボルト１
に設けられているネック部位置より、シアボルト１の頭
面１Ａ側位置又は通常ボルトの先端部に超音波反射部７
を設けていることから、該超音波反射部７は、ピンテー
ル３の有無にかかわらず、定位置に存在する。従ってこ
の超音波反射部７と、シアボルト１の頭面１Ａとの間で
シアボルトのねじ締付け前とねじ締付け後における超音
波伝搬時間測定し、これらの超音波伝搬時間を基にして
ボルトの伸び関係、つまりボルトの軸力が容易かつ精度
高く測定できる。
【００２３】従って例えば建築構造物を結合しているシ
アボルトの軸力を正確に測定することができるので、ね
じ締結を用いている建築構造物の信頼性の確保に大きく
寄与できると共に、初期締付け軸力測定や、軸力の経年
変化の測定が容易に行なえる。Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an accurate and easy-to-use axial force at the time of fastening bolts mainly used in building structures, transport vehicles such as trains and automobiles. The present invention relates to a bolt structure that can be measured at a time. [0002] For example, when constructing a building structure or the like using the fastening force of bolts and nuts, it is determined whether or not the bolts and nuts used for the fastening are tightened with a predetermined tightening torque. A method for measuring axial force using ultrasonic waves has been known as a means for detecting the force. [0003] First, the principle of measuring the axial force of a tightening bolt by ultrasonic waves will be described. Has a proportional relationship.
Therefore, the amount of elongation of the ultrasonic wave is converted into the amount of elastic elongation, and the converted amount of elongation is used as the bolt compliance (reciprocal of the spring constant).
To calculate the axial force. [0004] Therefore, for example, in a torcia-type high-strength bolt (hereinafter referred to as a shear bolt) widely used in a building structure or the like, there is a demand for measuring the axial force by ultrasonic waves. However, the conventional axial force measurement of the shear bolt has the following problems. [0005] That is, as shown in FIG.
A pin tail 3 is integrally formed at the tip of the shear bolt 1 with a neck portion 2 interposed therebetween. In order to integrally connect the fastened members 6A and 6B using the shear bolt 1, a nut 5 is screwed onto the shear bolt 1. When the members 6A and 6B are to be tightened, a tool is engaged with the pin tail 3 to prevent the rotation of the shear bolt 1, and the screw is tightened by the nut 5. The screw tightening is completed at the time of cutting at the neck. In order to measure the axial force of the shear bolts after the members 6A and 6B are fastened by the shear bolt 1 in this manner, as described above, the head surface 1A of the shear bolt 1 before and after fastening is applied to the head surface 1A. The measurement is performed by applying the ultrasonic sensor 4. The total length of the shear bolt before fastening is between the head surface 1A and the end surface 3A of the pin tail 3, and the total length of the shear bolt after fastening is determined by cutting the neck portion from the head surface 1A. Between the surface 2A and before and after fastening, the length of the shear bolt 1 changes. Therefore, even if an axial force is generated, the length of the bolt after the tightening is shorter than that before the tightening by the amount of the threaded pin tail 3, so that there is a problem that the correct axial force cannot be measured. The present invention has been made in view of such a conventional problem, and an axial force measuring bolt capable of accurately measuring the axial force of a shear bolt after fastening by using an ultrasonic sensor. It is intended to be provided. According to the present invention, there is provided a torsion-type high-strength bolt in which a pin tail is integrally formed at a tip end of a bolt with which a nut is engaged via a neck portion. Wherein the axial force measuring bolt has an ultrasonic reflecting portion formed at a position on the head side of the torcia-type high-strength bolt from the neck position. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to an embodiment shown in the drawings. The same parts of the structure of the present embodiment and the structure described in the conventional example will not be described. The description of the structure of the same structure is omitted by referring to the reference numeral used in the above. That is, in the present embodiment, the ultrasonic reflecting portion 7 is provided between the neck portion of the shear bolt 1 and the meshing portion of the nut 5. The ultrasonic reflector 7 may have any structure as long as it reflects ultrasonic waves emitted from the ultrasonic sensor 4 abutting on the head surface of the shear bolt 1 in the axial direction of the shear bolt 1. Although the through hole has a diameter of about 2 mm and penetrates in the diameter direction of the shear bolt 1, it is not limited to this, and may be a hollow hole, a slit, or the like. In this embodiment, the application position of the ultrasonic reflecting portion 7 is provided between the neck portion 2 and the screw engagement end portion of the nut 5. However, the present invention is not limited to this. May be a meshing portion. [0014] However, in order to measure the axial force of Shiaboruto, the position of the ultrasonic reflecting section 7 is, as much as possible the length <br/> faster than Shiaboruto 1 head surface 1A after the pintail 3 is cut Since it is desirable to be a distance, the position of the ultrasonic reflecting portion naturally becomes a position near the neck portion. Next, the procedure for measuring the axial force in the shear bolt 1 having the above structure will be described. First, a measurement preparation and a calibration experiment are performed. In the measurement preparation, the ultrasonic sensor 4 moves the head 1A of the shear bolt 1
The head face 1A of the shear bolt 1 is cut so as to be in close contact with. In the calibration experiment, the ultrasonic sensor 4 was installed on the head of the shear bolt 1, and then the shear sensor 1 was attached to the shear bolt 1.
A load is applied by a tensile tester or the like. The relationship between the ultrasonic wave propagation time difference before and after the application of the load and the shear bolt elongation is determined, and this is defined as a material constant. In actual measurement of the axial force of the shear bolt, the shear bolt 1 is set on the members 6A and 6B to be fastened, and the ultrasonic sensor 4 is brought into contact with the head surface 1A of the shear bolt 1 and the bolt ultrasonic wave before tightening is set. The propagation time is measured using the reflected wave from the ultrasonic reflecting unit 7. Next, the nut 5 is rotated until the pin tail 3 is cut off from the neck portion 2 by using a dedicated power screwdriver for the shear bolt 1. When the tightening is completed, the ultrasonic wave is applied to the head surface 1A of the screwed shear bolt 1 and the ultrasonic propagation time after the tightening is measured by using the reflected wave from the ultrasonic reflecting unit 7 in the same manner as before the tightening. I do. Thus, the axial force can be calculated from the shear bolt compliance and the like based on the difference between the ultrasonic wave propagation time before and after the shear bolt 1 is tightened and the material constant. As described above, according to the present invention, the shear bolt 1
The ultrasonic reflector 7 is located at a position closer to the head surface 1A of the shear bolt 1 or at the tip of the normal bolt than the neck portion provided at
Is provided, the ultrasonic reflecting portion 7 is at a fixed position regardless of the presence or absence of the pin tail 3. Therefore, between the ultrasonic reflecting portion 7 and the head face 1A of the shear bolt 1, the ultrasonic propagation time before and after the screw tightening of the shear bolt is measured, and the elongation relationship of the bolt is determined based on the ultrasonic propagation time. That is, the axial force of the bolt can be easily and accurately measured. [0023] Thus, for example because the axial force of the sheet <br/> Aboru in which you are bonded to the building structure can be accurately measured, greatly contributes to ensure the reliability of the building structure which uses a screw fastening In addition to this, it is possible to easily measure the initial tightening axial force and the aging of the axial force.
【図面の簡単な説明】
【図１】本発明の軸力測定ボルトの実施形態を示した説
明図。
【図２】本発明の軸力測定ボルトの実施形態を示した説
明図。
【図３】従来のシアボルトを使用するねじ締め態様を示
す説明図。
【図４】従来のシアボルトを使用するねじ締め態様を示
す説明図。
【符号の説明】
１…シアボルト ２…ネック部
３…ピンテール ４…超音波センサー
５…ナット ６Ａ，６Ｂ…被締結部
材
７…超音波反射部BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory view showing an embodiment of an axial force measuring bolt of the present invention. FIG. 2 is an explanatory view showing an embodiment of an axial force measuring bolt of the present invention. FIG. 3 is an explanatory view showing a screw tightening mode using a conventional shear bolt. FIG. 4 is an explanatory view showing a screw tightening mode using a conventional shear bolt. [Description of Signs] 1 Shear bolt 2 Neck 3 Pin tail 4 Ultrasonic sensor 5 Nut 6A, 6B Fastened member 7 Ultrasonic reflector
───────────────────────────────────────────────────── フロントページの続き (58)調査した分野(Int.Cl.7，ＤＢ名) F16B 31/02 G01L 5/24 ──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. 7 , DB name) F16B 31/02 G01L 5/24
Claims (1)
ック部を介してピンテールが一体形成されているトルシ
ア形高力ボルトにおいて、上記ネック部位置より該トル
シア形高力ボルトの頭部側位置に、超音波反射部を形成
してなることを特徴とする軸力測定ボルト。(1) A torsion-type high-strength bolt in which a pin tail is integrally formed at a tip end of a bolt with which a nut is engaged through a neck portion. An axial force measuring bolt characterized in that an ultrasonic reflecting portion is formed at a position on the head side of a high strength bolt.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP00317796A JP3535295B2 (en) | 1996-01-11 | 1996-01-11 | Axial force measurement bolt |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP00317796A JP3535295B2 (en) | 1996-01-11 | 1996-01-11 | Axial force measurement bolt |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH09196038A JPH09196038A (en) | 1997-07-29 |
| JP3535295B2 true JP3535295B2 (en) | 2004-06-07 |
Family
ID=11550115
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP00317796A Expired - Fee Related JP3535295B2 (en) | 1996-01-11 | 1996-01-11 | Axial force measurement bolt |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3535295B2 (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109459166B (en) * | 2018-10-17 | 2021-08-31 | 吴江市建设工程质量检测中心有限公司 | Ultrasonic detection method for high-strength bolt connection node in prefabricated assembly type structure |
| CN112179553B (en) * | 2020-09-09 | 2021-06-22 | 西南交通大学 | A method for ultrasonic simultaneous measurement of bolt axial force and shear force |
| IT202000024937A1 (en) * | 2020-10-22 | 2022-04-22 | Tokbo S R L | SENSORIZED CLAMPING ELEMENT |
| CN112763167A (en) * | 2020-12-31 | 2021-05-07 | 上海奥达科股份有限公司 | Method for confirming rigidity of bolt connected piece |
| TW202340753A (en) * | 2022-01-17 | 2023-10-16 | 日商Ｃａｓｔ股份有限公司 | Looseness detection system and sensor substrate |
-
1996
- 1996-01-11 JP JP00317796A patent/JP3535295B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH09196038A (en) | 1997-07-29 |
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| LAPS | Cancellation because of no payment of annual fees |